2-Methallyloxyphenol is a known intermediate for the synthesis of benzofuranyl insecticides, as disclosed in U.S. Pat. No. 3,474,170. In one process for producing 2-methallyloxyphenol by the reaction of methallyl chloride with catechol (also known as "pyrocatechol") as described in U.S. Pat. No. 3,474,171 and Hungarian Pat. No. 173,437, the reaction is conducted in an aliphatic ketone such as acetone or methyl ethyl ketone in the presence of a base as an acid acceptor and a catalyst such as potassium iodide. U.S. Pat. Nos. 4,250,333 and 4,618,728 describe various conditions for improving this reaction, including selection of solvent and base.
2-Methallyloxyphenol can undergo a Claisen rearrangement and subsequent ring closure in a known manner to form 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran, a precursor to carbofuran. Both of these reactions are conducted in the same solvent, usually an aromatic solvent such as xylene. An elevated temperature is required for the Claisen rearrangement to occur, and an acid catalyst is utilized in the second stage to effect cyclization.
European Patent Application No. 92,102 published Oct. 10, 1983 and U.S. Pat. No. 4,321,204 disclose single solvent systems for all three stages of the process, thus providing the benefit of avoiding costly isolation of 2-methallyloxyphenol and introduction of a second solvent. However, in EPA No. 92,102, an expensive quaternary phase transfer catalyst is required in the etherification step and the catalyst, because of its cost, must be separated for reuse before proceeding to the second and third stages. In U.S. Pat. No. 4,321,204 the single solvent is a polyhydroxy alkyl ether, requiring pressurization during the Claisen rearrangement.